Inflammatory reactions result from tissue (cell) injury or infection by foreign pathogens and show a series of complex physiological responses such as enzyme activation, inflammation mediator release, body fluid infiltration, cell movement and tissue destruction, and external symptoms such as erythema, edema, pyrexia, pain and etc., in which various inflammation-mediating factors and immune cells in local blood vessels and body fluids are involved. Also, in some cases, these inflammation reactions result in acute inflammation, granuloma, and chronic inflammations such as rheumatoid arthritis and osteoarthritis (Goodwin J. S. et al., J. Clin. Immunol., 9: 295-314, 1989).
Among enzymes having important effects on blood coagulation and inflammation, cyclooxygenase (hereinafter, referred to as ‘COX’) produces two main products, i.e., prostaglandin and thromboxane. Prostaglandin is an unsaturated fatty acid having various physiological activities and acts as local hormones or cell function regulators in the human body, such as inflammation and pain transmission, vasodilation, body temperature regulation, and gastric secretion stimulation (Marnett, L. J. et al., J. Biol. Chem., 274: 22903-22906, 1999). COX-1 plays an important role in the maintenance of cell homeostasis by maintaining normal physiological responses, such as gastrointestinal tract protection, renal blood flow regulation and platelet aggregation. Meanwhile, in a process wherein inflammation caused by external stimulus is transmitted, inducible isoenzyme COX-2 is temporarily expressed to release an excessive amount of prostaglandin at the site where inflammation occurs. Prostaglandin causes erythema, edema and pain, the main symptoms of inflammation, and has an activity of increasing the action of endogenous inflammatory mediator histamine, and the like. Thus, the inhibition of prostaglandin production at inflammatory sites can give much help in the treatment of inflammation.
Currently commercially available non-steroidal anti-inflammatory drugs (NSAIDs) aspirin, indomethacin, naproxen, ibuprofen and the like show anti-inflammatory effects by suppressing prostaglandin production through the inhibition of activity of COX-2 enzyme (Meade E. A. et al., J. Biol. Chem., 268: 6610, 1993). However, these NSAID drugs have problems in that they also inhibit COX-1 from playing an important role in maintaining the normal function of gastrointestinal tract and renal platelet, in addition to inhibiting COX-2 temporarily expressed by inflammatory stimulus, and thus cause severe side-effects, such as gastrointestinal tract bleeding and renal failure (Surh Y. J. et al., Mutation Research 480-481: 243-268, 2001). Accordingly, it is very important from an industrial point of view to find a natural substance that provides anti-inflammatory action while minimizing side effects.
Meanwhile, lignan refers to a group of natural compounds comprising n-phenyl propane bound to the β-position of the n-propyl side chain and is widely distributed in nature. There have been studies on the various physiological activities of lignan, such as blood glucose-lowering action, anticancer action, anti-asthmatic action and whitening action. For example, it was reported that lignans isolated from sesame, such as sesamin, episesamin, sesaminol, sesamolin and episesaminol, have anti-inflammatory effects (Korean Patent Laid-Open Publication No. 1997-7001043), and lignan compounds isolated from Magnoliae flos can be used as anti-asthmatic agents (Korean Patent Registration No. 0263439). Moreover, macelignan is a typical lignan compound found in Myristica fragrans (Tuchinda P. et al., Phytochemistry, 59: 169-173, 2002), and was reported to have various activities, such as the activation of caspase-3 inducing apoptosis (Park B. Y. et al., Biol. Pharm. Bull., 27(8): 1305-1307, 2004), and antioxidant action (Sadhu, S. K. et al., Chem. Pharm. Bull., 51(9): 595-598, 2003). However, there is still no report on the anti-inflammatory activity of lignan compounds, including macelignan.